Telephone transmitter



E. S. PRIDHAM.

TELEPHONE TRANSMITTER.

"memo" FILED ozc. 26. ma.

1,430,258. PatentedSept. 26, 1922.

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INVENTOR Edit/(L22 SPrid/ulm ATTORNEYS E. S. PRIDHAM.

TELEPHONE TRANSMITTER.

APPLICATION man 05c. 26, 1918.

1,430,258. Patented Sept. 26,1922.

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lilji 1 llll IIIHWHIIIIW l5 INVENTOR Edwin .SiPridkmn d fu ya cgjuumd ATTORNEYS Patented Sept. 26, 1922.

UNITED STATES PATENT OFFICE.

EDWI'HS. transmit, or oAxLANn, CALIFORNIA, Assro oa TO rim mAoNAvox 60., or sAN FRANCISCO, CALIFORNIA, A CORPORATION or AzarzoNA.

'rE nrnoNE TRANSMITTER.

Application died December 26, 1918. Serial No. 268,807.

To all whom it may concern:

Be it known that I, EDWIN S. PRIDHAM, a citizen of the United States residing at Oakland, in the county of Alameda and State of California, have invented new .and .usefullmprovements in Telephone Trainsmitters,of which the following is a spe'cification.

This invention relates totelephones and especially to .the transmitting element thereof. y

In application Serial Number 187,631,

filed August 21 1917, by Edwin S. Pridham and, Peter Jensen, there is disclosed a method. of and means for telephonically transmitting speech in an environment of extraneous noise. The transmitter therein described is shown witha very open construction, such that the diaphragm is ex- 2 o,- posed on both sides to the effects of the extraneous noise and is adapted to receive desired voice vibrations on one side only.

-The transmitter as disclosed in the above application; has proven to be remarkably1 e ective in operation, transmitting speec clearly and distinctly in environments of exceedingly distressing noise. However, in actual use, certain improvements in mechanical construction have suggested themselves and these improvements are. disclosed in the present a plication.

It is to'be understood, however, that the present invention is not limited to telephones of the construction and type illustrated in the foregoing application, since one of the chief 0b]eCtS of this invention is to rovide a telephone, whereby the transmitter is equally efiectivewhether the diaphragm is in a vertical plane or not.

A further object of the present invention is to'arrange for the housing and protection of. the transmitter button against the elements.

In the above mentioned application, Serial No.187 ,361, the transmitter is shown with the diaphragm exposed on both sides to the eifects of extraneous noise and the transmitter button is unprotected. Also,

the external circuit in a strong waterproof case-at the same time leavin the operatdiaphragm freely expose on both its si es to pressures dueto surrounding noise.

It is a well known fact that transmitters of the type employing buttons wherein two electrodes are spaced apart with resistance material between them, operate with the.

greatest efiiciency only when the electrodes are in a vertical-plane. When held in a horizontal plane, the resistance material tends to fall away from one electrode and the transmitter becomes either inoperative or o crates with low. efficiency; consequent y, it is the general practice to mount such transmitters so that in use the button electrodes are held practically in avertical plane. However, there are conditions of use where it is of the hi hest importance that the transmitter should operate with its dia hragm in either a horizintal or vertica plane. This is especially true of transmitters used in aeroplanesand balloons transmitter, which is the sub'ect of this specification, has been develope Having reference to the accompanying drawings:

Fig. 1 shows a cross, section in vertical plane of the transmitter.

Fig. 2 shows a side view of the transmitter in artial cross section.

Fig. 3 s owe a partial crosssection of the transmitter in horizontal position.

The transmitter as disclosed in the present invention is so constructed that the button with its electrical connections is mounted in a strong waterproof case, The operating diaphragm for the button is mounted in an open frame outside of the case so as to expose both of its sides to pressures due to extraneous sounds. An 0 crating link or arm extends from the diap ragm through a water-tight connection to the variable resistance element or button. The button within the casing is so mounted that the plane of the electrodes is perpendicular to the plane of the operating diaphragm. link or arm connects the diaphragm to the button in such a manner as to translate th" motion of the diaphragm to motion of one of the electrodes of the-button. It will be understood that in this manner the transrelation to the diaphragm.

I case 12 and the The button ,1 is provided with a shank 2 which is adjustably held in a bushing 3 by means of a set-screw 4. This bushing 1s fixed in a bridge 5. The back electrode 6 is inconnection with the bridge 5 and connection is 'made to the external circuit through a terminal 7. The front electrode 8 iscoljlnected to a terminal 9 which is insulated from the bridge 5, by means of a conneetor 1.0, and connection is made to the external circuit by means of a transmitter 25' cord 11. The top and bottom portions of the bridge 5 and 5 and as a means for astening the case 12. to the bridge. The upper portion of the bridge 5 has a central opening 13 which is of appreciabl greater diameter than the pin 14. 15 is a isc of slightly larger diameter than the disc forming t e upper part of the bridge 5*. The disc 15 has an opening of substantially equal diameter to the hole 13. Between the disc 15 and the bridge 5 is placed a gasket 16. This gasket fits snugly around the pin 14 and makes its entrance to the button chamber water-tight. Italso serves to make a water-ti ht connection between the disc 15. The holes through the disc 15 and 5' are of sufliciently lar er diameter than the pin 14 to allow the gas et which subtends the opening 13 to vibrate with the pin 14. The disc 15 is firmly held tor thg bridge 5 by means of the screws 1 1 The disc 15 isformed out on opposite sides into two narrow flanges 18-18. These flanges form a seat for a ring 20 which is fastened-to the flanges by means of screws In order to support the ap aratus in talking position, on the face of t e operator the flanges 18 are provided, which are extended to -form supports 21 upon which the cheek pieces 22? are ac lg ustabli mounted by means of, screws 23. hese c eek pieces 22 carry the studs' 24 over which suspension straps are snapped. In order to prevent the metal from coming into contact with the face and also to provide a cushioning effect, the cheek pieces 22 are covered with soft rubber pieces 25. This supporting arrangement c0nstiare flattened out to form circular discs which actz'as arotection to the button tutes the subject-matter of an independent application.

In ordinary tele hone practice where the transmitter is use the extensions 21 with the cheek pieces are omitted and the flanges 18 terminate at the edgeof the ring 20. The ring 20 forms a seat for the operating diaphragm 26 which is protected around the edge by the insulation 27 as in standard practice.

In a preferred type-of the transmitter which is shown in the drawings, the transmitter button 1 is mounted in the bridge 5 with the electrodes 6 and 8 in planes perpendicular to the plane of the dia hragm 26. The great advantage secured by this method of mounting is that the transmitter operates with the same efliciency in either a vertical .or horizontal position or any included position so long as the button remains in a vertical lane.

Suitable connections are provided between the diaphragm and the button for translating the vibrations of the diaphragm to the button. In the present instance I have shown an operating arm or link 28 connecting the 'diaphra and front electrode 8 of the transmltter button. This arm 28 is made of elastic material, such as spring brass or cop r. To one end is secured the threade pin 14. The diaphragm is clamped between 'the two nuts 29-29 to make a rigid connection to the pin. The other end is fastened to the base of the bridge by a screw 30.

The arm 28 is shaped to form a slight bow length to the front electrode 8 by means of an insulated bushing "31 and is held firmly thereto by the set-screw 32. It will be seen that any motion of the diaphragm 26 will cause a displacement of the front electrode 8. In this manner every variation of motion of the diaphragm 26 will be reproduced in motion of the front electrode of the button. p

In 7 actual practice, transmitters constructed as shown in the drawings have been used with the highest degree of suc-, cess, giving excellent articulation and be ing practically free from the disturbing ef fects of extraneous noise when used in telephone circuits.

The advantages secured by using this type of transmitter are: The button with its electrical connections are contained in a strong waterproof casing; the operating diaphragm is exposed on both sides to the effects of extraneous noise; and the mounting of the button in relation to the diaphragm makes it possible to use the transmitter in both vertical and horizontal positions or at any angle assumed by the diaphragm when turned on a horizontal diameter or axis.

variable resistance ,Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. In a'telephone transmitter, the combination-of a casing, a bridge or support mounted "within said casing, a transmitter button mounted in said bridge, an operating armconnected to said button, said arm extending outside of said casing, with an open frame mounted exteriorly on said casing, a diaphragm mounted in said frame, said diaphragm being so mounted in said frame that extraneous sounds have access to either side of said diaphragm for the purpose of balancing out said extraneous sounds, a connection between said diaphragm and said operating arm whereby sounds that have access to but one side of saiddiaphragm produce their full effect uponsaid transmitter button.

2. In a telephone transmitter, a casing, a transmitter button mounted within said casing, an open frame mounted exteriorly on said casing, a diaphragm mounted in said open frame so that sound vibrations may produce their effect upon either side of the diaphragm, an operating arm, conmeeting said diaphragm and said enclosed transmitter button, and means for positioning said transmitter that desired sound vibrations are restricted to but one side of said diaphragm. k 3. In a telephone transmitter, a casing, a button mounted within the casing, a frame mounted exteriorly on said casing, a diaphragm mounted in said frame so as to expose both of its sides to an extraneous sound vibration for the purpose of neutralizing the effect on the diahragm of said sound vibration, an opening in said casing, a gasket covering said opening, an operating pi extending through said gasket, said pin being connected to said diaphra m and in operative relation with said varia le resistance button.

4. In a telephone transmitter, a strong water-proof and soundproof casing, a transmitter button mounted within said casing,

an opening in said casing, an operatin pin extending throu h said opening and eing connected to said transmitter button, an.

- open frame-work mounted exteriorly on said casing, a diaphragm mounted in said open frame-work, said diaphragm being so mounted that both of its sides are exposed to the effect of an extraneous sound, said diaphragm being in operative relation with said pin.

5. n a telephone transmitter, ing elements in combination, a rated casing, an apertured frame mounted exteriorly on said casing, a transmitter button mounted within said non-perforated casing, a diaphragm mounted in said a ertured' frame, an operating arm exten ing the follownon-perfo-- soun from said transmitter buttonthrough said casing and connected to said diaphragm.

6. n a transmitter for use in noisy places, means for eliminating the effects of extraneous noises, comprising a diaphragm openly exposed on both of its sides to the e ect of said extraneous noises, a strong durable and waterproofing casing, a variable resistance element mounted within said casing, an opening in said casing, a pin extending through said opening and connecting said variable resistance element with said openl exposed diaphragm.

7. In a telep one transmitter, the combination of a diaphragm so mounted as to expose both of its sides to the effects of a pressure wave from an extraneous source of sound with an enclosed transmitter button, said button being mounted within a casing and protected from the effects of extraneous noises, and an operatin arm connectin said openly exposed iaphragm and said enclosed button.

8. In a telephone transmitter, a casing, a frame mounted exteriorly on said casing, a diaphragm so mounted in said frame as to expose both of its sides to extraneous sound vibrations and adapted to receive desired sound vibrations on one of its sides only, a bridge mounted within said casing, a transmitter button, said button comprising front and back spaced electrodes with resistance material between them, and a mounting for said transmitter button whereby said button is positioned on said bridge with the plane of its electrodes perpendicular to the plane of said exposed diaphragm, substantially as described.

9. In a telephone transmitter, a bridge, a frame mounted on said bridge, an operating diaphragm held in said frame, a transmitter button mounted on said bridge so posi tioned that the planes of electrodes of said button are perpendicular to the plane of said diaphragm, and an operating link con- 110 necting said diaphragm and said button, said link comprising a strip of material so connected between said button and said diaphragm that the direction of motion of said diap ragm is translated to a motion sub- 115 stantially perpendicular in direction for the operation of said transmitter button.

10. In a telephone transmitter, the combination of a diaphragm, a carbon resistance device for converting sound vibra- 120 tions of the diaphragm into electrical vibrations, a physical connection between said device and the diaphragm, means for insulatin said carbon resistance device from vibrations, except those transmitted 126 to it from the diaphragm, and means for mechanically supporting the diaphragm while permitting free access of sound vibrations to both sides thereof.

11. In a telephone transmitter, the com- 130 bination of a diaphragm supported to permil; free access of sound waves to both sides thereof, a variable resistance device for converting vibrations of the diaphra into electrical vibrations having 'a vibratory member responsive to vibrations transmitted to it from the diaphragm, a physical connection between the vibratory member of said device and the diaphragm for transmitting vibrations from the diaphragm to said member, and means for preventing sound Waves from afiecting the'vibratory member of said variable resistance device whereby said member is rendered responsive only to mechanical vibrations transmitted to it from the diaphragm.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

EDWIN S. PRIDHAM.

Witnesses:

JOHN H. HERRING, W. W. HEALEY. 

